It has taken several years and a lot of experimentation, (not to mention a lot of wasted film), but we finally have the answer for processing large, large format without a darkroom. The SP-8×10+ is a daylight safe tray system and doesn’t require any complicated frames or film holders and needs only 500ml of chemistry (even less, as reported by some of our beta testers!)

The highlights

Simplicity: Just take off the lid, drop in the film and put the lid back on. No messing with holders, frames or tubes. To be honest, handling 4×5 is pretty simple. But 8×10? That’s a whole new ballgame and we wanted to keep it simple.

Flexibility: Simple dividers keep smaller sheets separate. The production version will handle anything between 4×5 and 8×10: 5×7, 4×10, 4×5. Yeah, 9×12 will work too. You should be able to adapt it for those odd-ball sizes that no one else has heard off.

Proven: tray processing has been around since, well, forever. We’ve gotten the best results by just lifting the tray (with two hands) and “swirling” the liquid like a gold panner. You’ll also find that it’s a lot easier to load 8×10 film into a horizontal tray than a vertical tank.

We’ve launched a crowdfunding campaign to help fund the production effort, and mainly, to validate the market. The funding campaign ends on March 4th. If all goes well, we should be in production in June 2019.

The SP-8×10+ is so radically different than anything we’ve attempted before that it may be hard to believe that it’s a close relative of the SP-445. So how did we get here?

Product development

Our first attempt at a large, large format design was to just super-size the SP-445. We tried both a 5×7 and an 8×10 version. While test results where encouraging, the prototypes were awkward to handle, especially the SP-2810. The 1.5 liters of chemistry turned the agitation cycle into a workout but one of the biggest issues were the film holders.

We tried numerous designs and didn’t like any of them. It’s one thing to hold a sheet of film in a camera; it’s an entirely different battle trying to grip it underwater while being inverted. Besides, each size of film would require a special film holder which required a special mold. This complicated inventory issues and drove up costs.

Ergonomics aside, the production costs where skyrocketing. The mold for just the tank of the SP-2810 was going to weigh in at around 3000 lbs! Our next attempt was a modification to the “taco method”. While we build at least five different prototypes, our best results came with our adapter to that would hold two sheets of 5×7 in our SP-445 tank and an airfoil-shaped tube that held one sheet of 8×10. Both were easy to handle and not too tricky to load.

However, while the first results where encouraging, we started to see uneven development along the two edges where the “taco” almost touched. The anti-halation coating wasn’t getting completely washed off either. But the biggest issue was the limited functionality. The SP-257A could only do 5×7 and the SP-1810 could only process 8×10. We felt that the market demand a solution for both 5×7 and 8×10 and the combined tooling cost was just too high. Plus, there was the issue of customers having to buy a system for every size of film they wanted to use.

This might be a good time to address some of our marketing assumptions. The following comments are based on our limited surveys and research but we haven’t found anyone that has anything better.

  1. Very few people jump right into 8×10. Almost everyone starts large format with 4×5 (or maybe 9×12).
  2. Everyone (well at least 95%) of people shooting 8×10 also shoot some 4×5.
  3. The majority of 4×5 shooters using the SP-445 do not have a real darkroom. The majority of 8×10 users have a complete, rather fancy, darkroom.
  4. Our best guess is that the market for 8×10 is about half the size of 4×5; the market for 5×7 is about a quarter of it. Of course, there is overlap.

Given the above information, we decided to focus on a system that could handle anything 8×10 or smaller. We wanted to focus on making it easy to handle, chemistry efficient and flexible. And it would be nice if it could handle two sheets of 8×10 at once.


So we tossed out everything we had tried and started fresh. It seemed that the freshest place to start was at the beginning: tray processing.

Well, we tossed out just about everything: it seemed obvious that we’d need a film holder of some sort to keep the film in place. Sometimes, the best lesson you can learn is that you’re wrong. We didn’t need a film holder.

Note to self: film is heavier than water

Our measurements give a rough mass of 1.5 grams/cm3. Water, by definition, has a density of 1.0 grams/cm3. Thus film sinks (once you get past the surface tension of the water). Now before you argue that your film is always floating up and out of the wash tray: it’s not. It’s being moved around by the currents in the tray; in still water, it will sink.

Surface tension is our friend. Well, it is once you get under the liquid. The big trick is getting the film under the developer quickly and evenly. Since this is a daylight safe tray, you can’t just push it under like Ansel did.

Here’s where surface tension comes in: just pre-soak the film. Once the film is wet, it flattens out and sinks; as you drain the water, surface tension between the back of the film and the bottom of the tray will hold it down as you refill the tray.

Once the film is submerged again, the surface tension is gone and liquid is allowed under the film to wash away any anti-halation coating. The film is also free to slide around in the solution, which helps ensure even development and removal of the dreaded anti-halation coating.

This has worked extremely well with 8×10; pretty well with 5×7; not so well with 4×5. The 4×5 is so small and light that it tends to float. Once it’s under the solution it’s fine. So we’ve experimenting with different “hold down fingers” or “tabs” to keep the film from rising up during the pre-soak step. This isn’t a big deal since we need some sort of dividers to keep the sheets separate anyway.

Some things are easier to do horizontally than vertically; handling 8×10 film is one of them.

All the tanks we tried required loading vertically. This required a really large darkbox (or a real darkroom). By switching to the tray architecture, we can get by with a much smaller (shorter) darkbox.

We just lay the film holder next to the SP-8×10+; slide the film out of the film holder; slide it into the tray and put on the lid. Must less likely to scratch the film than when you have flip things ninety degrees or rotate it around.

What about two sheets of 8×10?

Okay, we knew you were going to ask. We tried. We really, really tried. It sounds simple: just stack one sheet on top of the other. However, after to many different designs and over fifty sheets of 8×10 (and we’re not even counting the 5×7 and 4×5 sheets), we decided it wasn’t going to happen.

With some film/chemistry combinations, we got decent results, but with other film/chemistry combos, we got uneven development. In some cases, you could even see a “shadow” of the film holder on the lower negative. Unfortunately, even the good results were highly dependent on the agitation technique used.

It took a lot of liquid, over 1200 ml. That’s two to three times the minimum required for a single sheet. In fact, we’ve successfully processed a single sheet in only 400 ml.
Not everyone was that enthused about a two sheet solution. Our marketing data shows that only 15% required a two sheet system.

In fact, another 15% said they’d never process two sheets at once. Some of these are the serious shooters that are exposing for n-1, n+2 etc and want to process each sheet separately. Others just don’t shoot that much 8×10 or don’t want to risk two sheets in the soup at the same time.

The rest said it was a neat feature but not essential. We’ll just have to wait and see how accurate our data was.
So, in order to keep things simple and affordable, we dropped the two sheet design goal.

What’s left?

The biggest unknowns are the hold down tabs. The current design works well but we foresee some production issues. There’s also the need to accommodate all the legacy sizes of film that are still in use. So we’ll be reviewing that part of the design. Certainly not a show-stopper.

The current prototypes are 45mm tall. We choose that height with the intend of processing two sheets at once. Since that is no longer a design requirement, we might lower it. This would also make it easier to attach the hold down tabs to the lid. We’re still experimenting.

So far the test results and the preliminary sales results are encouraging. Questions and comments are always welcome. Please spread the word to your large format friends and check it out here.

~ Tim

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1 COMMENT

  1. No offense, but the video on their website is really…. I mean has room for improvements. Firstly, the audio is terrible (get the free Audacity and clean the noise). Then, I see some tupperware type containers. I suggest they do a real demo. Load the film (just that film he has is fine), put water as developer and fixer in the tank and show the procedure.

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